1. Field of the Invention
The present invention relates generally to testing body fluids. Particularly, the present invention relates to a lancet used for obtaining a sample of body fluid for testing. More particularly, the present invention relates to a lancet and test strip combination. Still more particularly, the present invention relates to a diagnostic system incorporating a lancet and test strip combination and an electronic meter.
2. Description of the Prior Art
The examination of blood samples in clinical diagnostics enables the early and reliable recognition of pathological states as well as a specific and well-founded monitoring of physical condition. Lancets and lancet devices enable blood sample collection especially for home monitoring by diabetics.
A blood sugar level that is either too high or low can lead to adverse physical consequences for a diabetic. Personal blood sugar determination is important for diabetics to aid in controlling and maintaining blood sugar levels with the use of insulin and other medications. A lancet is used to pierce the skin (usually a finger) and produce a small blood sample. Lancing the skin is painful. For diabetics who are required to test their blood sugar level several times a day, lancing several times a day is a painful but necessary procedure. The blood sample is then placed on a test strip for analysis and the blood glucose level is read by a blood glucose meter. Various devices have been devised for lancing the skin of a user as well as combination devices that include lancets and analytical device.
U.S. Pat. No. 6,620,112 (2003, Klitmose) discloses a disposable lancet combined with a reagent carrying strip which carries a reagent that indicates the concentration of a blood component in a blood sample placed in contact with the strip The reagent carrying strip is connected to the lancet, e.g. by molding. One end of the lancet is sharpened for piercing the skin. The strip is sheet-like and has a first side and a second side, which sides are both accessible for the user, such that the reagent carrying strip can be inserted into a blood glucose meter. A weakened tear line is provided at a connection between the lancet and an edge of the reagent carrying strip so that the reagent carrying strip may be easily disconnected from the lancet.
U.S. Patent Application Publication No. US2003/0050573 (Kuhr et al.) discloses an analytical device containing a lancet comprising a lancet needle and a lancet body, the lancet needle being movable relative to the lancet body and the lancet body being composed, at least in the area of the tip of the lancet needle, of an elastic material in which the tip of the lancet needle is embedded, and an analytical test element which is permanently connected to the lancet body. In addition the invention concerns an analytical device containing a lancet comprising a lancet needle and lancet body which is in the form of a hollow body in the area of the tip of the lancet needle and surrounds the tip of the lancet needle, the lancet needle being movable relative to the lancet body and the hollow body being composed at least partially of an elastic material, and an analytical test element which is permanently connected to the lancet body.
U.S. Pat. No. 6,607,658 (2003, Heller et al.) discloses an analyte measurement device includes a sensor strip combined with a sample acquisition device to provide an integrated sampling and measurement device. The sample acquisition device includes a skin piercing member such as a lancet attached to a resilient deflectable strip which may be pushed to inject the lancet into a patient's skin to cause blood flow. The resilient strip is then released and the skin piercing member retracts.
U.S. Patent Application Publication No. 2002/0130042 (Moerman et al.) discloses an apparatus having a meter unit, a lancet and an electrochemical sensor. The meter is reusable while the lancet and the electrochemical sensor are incorporated into assemblies intended for single use. The meter has a housing within which a lancet is engaged with a mechanism for moving the lancet, a connector disposed within the housing for engaging an electrochemical sensor specific for the analyte, and a display operatively associated with a connector for displaying the amount of the analyte to the user.
U.S. Patent Application Publication No. 2002/0082522 (Douglas et al.) discloses a device and method for lancing a patient, virtually simultaneously producing and collecting a small fluid sample from the body. The device includes a lancing needle, drive mechanism, kneading or vibration mechanism, optional suction system, and sample ejection mechanism.
A disadvantage of the above prior art is that each of the lancets are rigid and rely solely on the spring action of a firing mechanism to retrieve the lancet after firing or, in the case of the Heller device, the specimen piercing speed of the lancet is uncontrolled and depends on the quickness of the user. Further, the prior art that provides for shallow depth penetration of the lancet generally includes a sophisticated system to knead the surrounding lanced area by ultrasonic action, piezo-electric or mechanical oscillation to stimulate the blood flow from the wound to draw the blood into a pumping system. It should also be noted that none of the prior art lancet sensor combination devices are currently available in the marketplace, which indicates that the prior art devices do not provide a reasonable, cost-effective, useful, and workable system for a lancet sensor combination test strip and meter.
Currently available, prior art, blood glucose meters include those known as the Accu-Chek® Aviva system by Roche Diagnostics, the One-Touch® system by LifeScan, the Glucometer® DEX system by Bayer, the True Track® system by Home Diagnostics, and the Freestyle® system by Abbott. Although these meters advertise various advantages such as fast and reliable test results, small volume requirements and reduced pain systems, each of the currently available meters requires the use of a separate lancing device to obtain the blood sample from the patient. Some require the occasional use of a control reagent to calibrate the meter. All, however, require a patient to carry both the meter and the lancing device with the appropriate number of disposable test strips and lancets. None of these currently available meters, on the other hand, are capable of accepting a combination lancet sensor test strip or eliminating the need for a separate lancing device.
Therefore, what is needed is a lancet assembly that has an inherent return action upon piercing a specimen. What is further needed is a lancet assembly that can incorporate an analytical test strip. What is also needed is a test strip diagnostic, handheld meter that is capable of driving a lancing device and electronically testing a blood sample. What is still needed is a diagnostic, handheld meter that is usable with a lancet sensor test strip combination.